This invention relates to an apparatus for slicing fruit. More particularly, this invention relates to an apparatus and method for severing a piece of fruit into hemispherical sections with a pressurized fluid stream.
In the produce industry and in particular the cherry processing industry, an effort is made for preservation as quickly as possible after harvest. Since the harvest season is relatively short, the cherries are usually frozen for processing later in the season. Cherry slicing is a processing step which is usually accomplished later in the season with the cherries in their frozen form.
Certain processing steps are preferably performed before the cherries become frozen. Particularly, the pitting operation is performed immediately after harvest. Pitting is ordinarily performed with a pitting needle having six blades arranged in a conical configuration. The needle passes through the pulp of the cherry to engage the pit. The pit is then forced through an end of the cherry.
Different cherries react differently to the pitting needle. Sour cherries are generally round with round shaped pits and are readily pitted by the pitting needle. Others, such as Napoleon cherries, have a heart shaped pit. For these cherries, the pitting needle is less efficient. However, all cherries have the problem of off-center pits and misshaped pits. The problem is thus encountered that some cherries with pits are not properly depitted and make their way to the freezing apparatus. Even though advances have been made in the art of pit detection, pits occasionally avoid detection and continue for further processing.
After pitting, the next step in cherry processing is freezing. Cherries are frozen with an IQF or Individual Quick Freeze process. Using this process, the cherries are individually frozen so that they will not stick together. The cherries are then transported for storage until later in the season.
One of the processing steps deferred until later in the season is slicing. Slicing is performed while the cherries are still frozen. The cherries are then canned or deposited into freezer bags for transport.
Traditional methods for slicing a cherry include the use of a 5-inch rotating cutting wheel. For this method, individual cherries are directed along a transport to the cutting wheel. The cutting wheel then engages the cherry to slice it in two. This method has considerable drawbacks. The blade must be very thin to produce a smooth incision into the fruit without significant deformation thereto. A relatively sharp blade must also be used to penetrate the thin, taut skin of the fruit and the softer pulp. Unfortunately, metal blades have a tendency to dull with continued use. Constant resharpening is thereby required.
Due to the drawbacks of the pitting technology, a small percentage of cherries pass to the cutting wheel with the pit still inside. Consequently, as the rotating blade contacts the pit, the pit is either sliced or shattered into a plurality of separate pieces. These separate pieces are difficult to remove from the cherry mixture. Ultimately, these pit fragments find their way to the consumer. Dullness of the rotating blade is also accelerated through contact with the pit. This requires additional sharpening and increases the associated down time.
A more serious problem occurs as the cutting wheel contacts the cherry pit. Metal fragments may be chipped from the rotating blade. Metal fragmentation severely decreases the useful life of the cutting wheel. Additionally, metal fragments pose a serious health risk due to the potential for consumer ingestion.
Water jet technology has previously been used in food processing applications. In one application, a modified water jet is used to remove the pits from olives. The oblong olives are first positioned in a holding rack while a thin stream of water shoots along the longitudinal axis in a circular direction. The water stream cuts a tubular section through the olive which surround the pit. This tubular section is then separated from the remaining olive portion with a mechanical or water stream punch.
The operation of this mechanism is fairly complex and requires substantial maintenance. The olive must also be extensively manipulated to fit within the holding rack. This mechanism does not readily lend itself to the cherry processing industry due to the irregular pit size and differences in fruit shape. Specifically, since the cherry is generally round, the force of the fluid stream has the tendency of dislodging the cherry from the holding rack.
Water jet technology has also been used for slicing other foods such as frozen pies. The frozen pies are arranged on a grid as a water carriage cuts the desired sections. Since the pies are relatively heavy, the water stream can efficiently slice the pies without dislodging them from the grid. This type of mechanism is also inapplicable to the cherry processing industry due to the tendency of the cherries to dislodge from the grid under force from the fluid jet.